usps costs of priority mail vary based on factors such as the size, weight, and destination of the package. Priority Mail is one of USPS’s most popular services, offering fast and reliable delivery within the United States. The cost for Priority Mail starts at $9.35 for a small flat-rate box and increases with the size and weight of the package. For larger packages, USPS charges based on the weight and the destination, with prices typically increasing for shipments traveling long distances. Priority Mail offers delivery within 1 to 3 business days and includes tracking and insurance coverage for packages up to $50 in value. Additionally, customers can take advantage of free shipping supplies, such as boxes and envelopes, from USPS when using Priority Mail. The costs for Priority Mail services can be calculated using the USPS Postage Price Calculator, which provides accurate pricing based on package details.